nfs-utils: declare a static common buffer for nfssvc.c routines

Several of the routines in nfssvc.c declare a buffer for strings. Use a
shared static buffer instead to keep it off of the stack. Also, the
buffer allocated in some places is *really* large. BUFSIZ is generally
8k. These routines don't need nearly that much.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

diff --git a/utils/nfsd/nfssvc.c b/utils/nfsd/nfssvc.c
index 0a7546a3c6f53544f65b65a564dc16a4f7308577..025554d6fa118530c1026d9313f01d1c090f0807 100644 (file)
--- a/utils/nfsd/nfssvc.c
+++ b/utils/nfsd/nfssvc.c
@@ -24,18 +24,25 @@
 #define NFSD_VERS_FILE    "/proc/fs/nfsd/versions"
 #define NFSD_THREAD_FILE  "/proc/fs/nfsd/threads"
 
+/*
+ * declaring a common static scratch buffer here keeps us from having to
+ * continually thrash the stack. The value of 128 bytes here is really just a
+ * SWAG and can be increased if necessary. It ought to be enough for the
+ * routines below however.
+ */
+char buf[128];
+
 static void
 nfssvc_setfds(int port, unsigned int ctlbits, char *haddr)
 {
        int fd, n, on=1;
-       char buf[BUFSIZ];
        int udpfd = -1, tcpfd = -1;
        struct sockaddr_in sin;
 
        fd = open(NFSD_PORTS_FILE, O_RDONLY);
        if (fd < 0)
                return;
-       n = read(fd, buf, BUFSIZ);
+       n = read(fd, buf, sizeof(buf));
        close(fd);
        if (n != 0)
                return;
@@ -91,7 +98,7 @@ nfssvc_setfds(int port, unsigned int ctlbits, char *haddr)
                }
        }
        if (udpfd >= 0) {
-               snprintf(buf, BUFSIZ,"%d\n", udpfd); 
+               snprintf(buf, sizeof(buf), "%d\n", udpfd); 
                if (write(fd, buf, strlen(buf)) != strlen(buf)) {
                        xlog(L_ERROR, 
                               "writing fds to kernel failed: errno %d (%m)", 
@@ -103,7 +110,7 @@ nfssvc_setfds(int port, unsigned int ctlbits, char *haddr)
        if (tcpfd >= 0) {
                if (fd < 0)
                        fd = open(NFSD_PORTS_FILE, O_WRONLY);
-               snprintf(buf, BUFSIZ,"%d\n", tcpfd); 
+               snprintf(buf, sizeof(buf), "%d\n", tcpfd); 
                if (write(fd, buf, strlen(buf)) != strlen(buf)) {
                        xlog(L_ERROR, 
                               "writing fds to kernel failed: errno %d (%m)", 
@@ -118,7 +125,7 @@ static void
 nfssvc_versbits(unsigned int ctlbits, int minorvers4)
 {
        int fd, n, off;
-       char buf[BUFSIZ], *ptr;
+       char *ptr;
 
        ptr = buf;
        off = 0;
@@ -128,17 +135,17 @@ nfssvc_versbits(unsigned int ctlbits, int minorvers4)
 
        for (n = NFSD_MINVERS; n <= NFSD_MAXVERS; n++) {
                if (NFSCTL_VERISSET(ctlbits, n))
-                   off += snprintf(ptr+off, BUFSIZ - off, "+%d ", n);
+                   off += snprintf(ptr+off, sizeof(buf) - off, "+%d ", n);
                else
-                   off += snprintf(ptr+off, BUFSIZ - off, "-%d ", n);
+                   off += snprintf(ptr+off, sizeof(buf) - off, "-%d ", n);
        }
        n = minorvers4 >= 0 ? minorvers4 : -minorvers4;
        if (n >= NFSD_MINMINORVERS4 && n <= NFSD_MAXMINORVERS4)
-                   off += snprintf(ptr+off, BUFSIZ - off, "%c4.%d",
+                   off += snprintf(ptr+off, sizeof(buf) - off, "%c4.%d",
                                    minorvers4 > 0 ? '+' : '-',
                                    n);
        xlog(D_GENERAL, "Writing version string to kernel: %s", buf);
-       snprintf(ptr+off, BUFSIZ - off, "\n");
+       snprintf(ptr+off, sizeof(buf) - off, "\n");
        if (write(fd, buf, strlen(buf)) != strlen(buf))
                xlog(L_ERROR, "Setting version failed: errno %d (%m)", errno);
 
@@ -168,9 +175,8 @@ nfssvc(int port, int nrservs, unsigned int versbits, int minorvers4,
                 * Just write the number in.
                 * Cannot handle port number yet, but does anyone care?
                 */
-               char buf[20];
                int n;
-               snprintf(buf, 20,"%d\n", nrservs);
+               snprintf(buf, sizeof(buf), "%d\n", nrservs);
                n = write(fd, buf, strlen(buf));
                close(fd);
                if (n != strlen(buf))